<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    div {
      display: flex;
      width: 600px;
      height: 400px;
      background-color: pink;
      /* flex布局中，默认的子元素是不换行的 ，如果装不开，会缩小子元素的宽度，放到父元素里面 */
      /* flex-wrap: nowrap; */
      flex-wrap: wrap;
    }


  div span {
            width: 150px;
            height: 100px;
            background-color: purple;
            color: #fff;
            margin: 10px;
        }
  </style>
</head>
<body>
  <div>
    <span>1</span>
    <span>2</span>
    <span>3</span>
    <span>3</span>
    <span>3</span>
</div>
</body>
</html>